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<DIV><FONT face=Arial size=2>Dear colleagues, dear Holger,</FONT></DIV>
<DIV><FONT face=Arial size=2>in my long working period (now I'm anymore
practical active and also I will not appear in Uppsula since my
</FONT></DIV>
<DIV><FONT face=Arial size=2>historical talk Darwin/Svedbergcoudn't find a
place in the programm) several times I was confrontated with
</FONT></DIV>
<DIV><FONT face=Arial size=2>the phenomena of sedimentation and floatating
components-particles of the same sample. In my cases </FONT></DIV>
<DIV><FONT face=Arial size=2>"clients" were interessted to caracterize
molecular msses in aqueous solutions and also to detemie the
positive-sedimenting and the negative sedimenting/floatating particles and
even to test, if partly exist a complex of both
components that are assembled with an average density, that in
certain cases will either sediment or floated , total-standstill !
This systems to analyse you need to invest a lot of runs in
several mixed solvents.</FONT></DIV>
<DIV><FONT face=Arial size=2>I used the following proceedure.
In case of analysing the sample in D<FONT size=1>2</FONT>O buffer
you need use a10 fold</FONT></DIV>
<DIV><FONT face=Arial size=2>concentated buffer and a 10fold concentrated
sample, so you get at the end an 80% D<FONT size=1>2</FONT>O solution
density</FONT></DIV>
<DIV><FONT face=Arial size=2>with your desiered end concentration. this
procedure you must repeat at several smaller D<FONT size=1>2</FONT>O
concentrations</FONT></DIV>
<DIV><FONT face=Arial size=2>to show graphically the extrapolated
particle-density of your desiered particle [<SPAN lang=EN-GB
style="FONT-SIZE: 12pt; FONT-FAMILY: 'Times New Roman'; mso-fareast-font-family: 'Times New Roman'; mso-ansi-language: EN-GB; mso-fareast-language: DE; mso-bidi-language: AR-SA">A
method of<SPAN style="mso-spacerun: yes"> </SPAN>S<SPAN lang=EN-GB
style="FONT-SIZE: 12pt; FONT-FAMILY: 'WP Greek Courier'; mso-fareast-font-family: 'Times New Roman'; mso-ansi-language: EN-GB; mso-fareast-language: DE; mso-bidi-language: AR-SA; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'; mso-bidi-font-family: 'Times New Roman'; mso-char-type: symbol; mso-symbol-font-family: 'WP Greek Courier'"><SPAN
style="mso-char-type: symbol; mso-symbol-font-family: 'WP Greek Courier'">0</SPAN></SPAN></SPAN><SPAN
lang=EN-GB
style="FONT-SIZE: 12pt; FONT-FAMILY: 'Times New Roman'; mso-fareast-font-family: 'Times New Roman'; mso-ansi-language: EN-GB; mso-fareast-language: DE; mso-bidi-language: AR-SA">
(</SPAN><SPAN lang=EN-GB
style="FONT-SIZE: 12pt; FONT-FAMILY: 'WP Greek Courier'; mso-fareast-font-family: 'Times New Roman'; mso-ansi-language: EN-GB; mso-fareast-language: DE; mso-bidi-language: AR-SA; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'; mso-bidi-font-family: 'Times New Roman'; mso-char-type: symbol; mso-symbol-font-family: 'WP Greek Courier'"><SPAN
style="mso-char-type: symbol; mso-symbol-font-family: 'WP Greek Courier'">0</SPAN></SPAN><SPAN
lang=EN-GB
style="FONT-SIZE: 12pt; FONT-FAMILY: 'Times New Roman'; mso-fareast-font-family: 'Times New Roman'; mso-ansi-language: EN-GB; mso-fareast-language: DE; mso-bidi-language: AR-SA">=<SPAN
style="mso-spacerun: yes"> </SPAN>viscosity) versus ρ at<SPAN
style="mso-spacerun: yes"> </SPAN>several<SPAN
style="mso-spacerun: yes"> </SPAN>D</SPAN><SPAN lang=EN-GB
style="FONT-SIZE: 9pt; FONT-FAMILY: 'Times New Roman'; mso-fareast-font-family: 'Times New Roman'; mso-ansi-language: EN-GB; mso-fareast-language: DE; mso-bidi-language: AR-SA">2</SPAN><SPAN
lang=EN-GB
style="FONT-SIZE: 12pt; FONT-FAMILY: 'Times New Roman'; mso-fareast-font-family: 'Times New Roman'; mso-ansi-language: EN-GB; mso-fareast-language: DE; mso-bidi-language: AR-SA">O
/ H</SPAN><SPAN lang=EN-GB
style="FONT-SIZE: 9pt; FONT-FAMILY: 'Times New Roman'; mso-fareast-font-family: 'Times New Roman'; mso-ansi-language: EN-GB; mso-fareast-language: DE; mso-bidi-language: AR-SA">2</SPAN><SPAN
lang=EN-GB
style="FONT-SIZE: 12pt; FONT-FAMILY: 'Times New Roman'; mso-fareast-font-family: 'Times New Roman'; mso-ansi-language: EN-GB; mso-fareast-language: DE; mso-bidi-language: AR-SA">O<SPAN
style="mso-spacerun: yes"> </SPAN>concentrations described<SPAN
style="mso-spacerun: yes"> </SPAN>1971<SPAN
style="mso-spacerun: yes"> </SPAN>Huang<SPAN
style="mso-spacerun: yes"> </SPAN>et<SPAN style="mso-spacerun: yes">
</SPAN>al. (.ref<SPAN style="COLOR: black">: C H<SPAN
style="mso-spacerun: yes"> </SPAN>Huang and J Charlton<SPAN
style="mso-spacerun: yes"> </SPAN>(JBC 1971<SPAN
style="mso-spacerun: yes"> </SPAN>vol 216<SPAN
style="mso-spacerun: yes"> </SPAN>8<SPAN style="mso-spacerun: yes">
</SPAN>April] and used for the determination of </SPAN>ρ of<SPAN
style="mso-spacerun: yes"> </SPAN>vesicles)</SPAN></FONT></DIV>
<DIV><FONT face=Arial size=2><SPAN lang=EN-GB
style="FONT-SIZE: 12pt; FONT-FAMILY: 'Times New Roman'; mso-fareast-font-family: 'Times New Roman'; mso-ansi-language: EN-GB; mso-fareast-language: DE; mso-bidi-language: AR-SA"> A
similar proceedure is also possible to make by using
precise sucrose concentrations, only in that case the precise
viscosity of each solution ( S<SPAN lang=EN-GB
style="FONT-SIZE: 12pt; FONT-FAMILY: 'WP Greek Courier'; mso-fareast-font-family: 'Times New Roman'; mso-ansi-language: EN-GB; mso-fareast-language: DE; mso-bidi-language: AR-SA; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'; mso-bidi-font-family: 'Times New Roman'; mso-char-type: symbol; mso-symbol-font-family: 'WP Greek Courier'"><SPAN
style="mso-char-type: symbol; mso-symbol-font-family: 'WP Greek Courier'">0</SPAN></SPAN>
) is hard , unknown is also if the sucrose
dose not</SPAN></FONT></DIV>
<DIV><FONT face=Arial size=2><SPAN lang=EN-GB
style="FONT-SIZE: 12pt; FONT-FAMILY: 'Times New Roman'; mso-fareast-font-family: 'Times New Roman'; mso-ansi-language: EN-GB; mso-fareast-language: DE; mso-bidi-language: AR-SA">influence
biochemically the particles.</SPAN></FONT></DIV>
<DIV><FONT face=Arial size=2><SPAN lang=EN-GB
style="FONT-SIZE: 12pt; FONT-FAMILY: 'Times New Roman'; mso-fareast-font-family: 'Times New Roman'; mso-ansi-language: EN-GB; mso-fareast-language: DE; mso-bidi-language: AR-SA">Knowing
the real particle density solves the main obstacle to
determine such sedimenting/floating</SPAN></FONT></DIV>
<DIV><FONT face=Arial size=2><SPAN lang=EN-GB
style="FONT-SIZE: 12pt; FONT-FAMILY: 'Times New Roman'; mso-fareast-font-family: 'Times New Roman'; mso-ansi-language: EN-GB; mso-fareast-language: DE; mso-bidi-language: AR-SA">components
in one solution. Yours...ariel</SPAN></FONT></DIV>
<DIV><FONT face=Arial size=2><SPAN lang=EN-GB
style="FONT-SIZE: 12pt; FONT-FAMILY: 'Times New Roman'; mso-fareast-font-family: 'Times New Roman'; mso-ansi-language: EN-GB; mso-fareast-language: DE; mso-bidi-language: AR-SA"><A
href="mailto:ariel.lustig@bluewin.ch">ariel.lustig@bluewin.ch</A></SPAN></FONT></DIV></BODY></HTML>